Abstract:

A method for discharging an electronic device on a substrate is provided.
A metal pin mounted on a wire bonder is used to touch with a specific
finger disposed on the substrate which is in electrical connection with
the electronic device. As a result, the electric charge previously stored
in the electronic device will be conducted to the wire bonder through the
specific finger and metal pin thereby discharging the stored charge.
Another method for discharging an electronic device on a substrate is
also provided. A metal wire protruding out from the capillary of a wire
bonder is heated to form a metal ball at the capillary. The capillary is
moved to bring the metal ball into contact with the specific finger. As a
result, the electric charge previously stored in the electronic device
will thus can be discharged to the wire bonder. The present invention
further provides a semiconductor package.

Claims:

1. A method for discharging an electronic device on a substrate, the
substrate having a finger thereon which is electrically connected to the
electronic device, the method comprising the steps of:providing a wire
bonder having a metal pin electrically connecting to the wire bonder;
andbringing the metal pin into electrical contact with the finger on the
substrate so that the charge previously stored in the electronic device
can be conducted to the wire bonder through the finger and the metal pin
thereby discharging the stored charge.

2. The method as claimed in claim 1, wherein the electronic device is a
capacitor.

3. A method for discharging an electronic device on a substrate, the
substrate having a finger thereon which is electrically connected to the
electronic device, the method comprising the steps of:providing a wire
bonder having a capillary and a metal wire protruding out from the
capillary; andbringing the metal wire protruding out from the capillary
into electrical contact with the finger so that the charge previously
stored in the electronic device can be conducted to the wire bonder
through the finger and the metal wire thereby discharging the stored
charge.

4. The method as claimed in claim 3, wherein the step of bringing the
metal wire into electrical contact with the finger comprising:heating the
metal wire protruding out from the capillary to form a metal ball at the
capillary; andbringing the metal ball into electrical contact with the
finger.

5. The method as claimed in claim 3, wherein the electronic device is a
capacitor.

6. The method as claimed in claim 4, wherein the electronic device is a
capacitor.

7. A semiconductor package, comprising:a substrate;a chip disposed on the
substrate;an electronic device disposed on the substrate;a finger
disposed on the substrate and electrically connected to the electronic
device, the finger having a first portion and a second portion;a metal
ball formed on the first portion of the finger;a metal wire electrically
connecting the chip to the second portion of the finger; anda sealant
formed on the substrate and encapsulating the chip, metal ball, metal
wire, finger and electronic device.

8. The semiconductor package as claimed in claim 7, wherein the metal ball
is formed by the steps comprising:heating a metal wire protruding out
from a capillary of a wire bonder to form a metal ball at the
capillary;bringing the metal ball into contact with the finger;
andseparating the metal wire protruding out from the capillary from the
metal ball on the finger.

9. The semiconductor package as claimed in claim 7, wherein the electronic
device is a capacitor.

10. The semiconductor package as claimed in claim 8, wherein the
electronic device is a capacitor.

Description:

CROSS REFERENCE TO RELATED APPLICATION

[0001]This application claims the priority benefit of Taiwan Patent
Application Serial Number 096120685 filed Jun. 8, 2007, the full
disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002]1. Field of the Invention

[0003]The invention relates to a method for discharging electronic
devices, and more particularly, to a method for discharging electronic
devices on a substrate. The invention also relates to a semiconductor
package.

[0004]2. Description of the Related Art

[0005]According to conventional semiconductor package processes, in order
to electrically connect a chip to the substrate on which the chip is
mounted, a wire bonder is typically used to connect wires from the chip
to the substrate. Generally, to make easy to achieve the wire bonding,
one end of a bonding wire is first bonded to one of the bonding pads on
the chip and the other end of the bonding wire is then bonded to the
corresponding finger on the substrate. However, some devices, such as
capacitors mounted to the substrate may have been fully charged prior to
the wire bonding process. In the event that the charged capacitors have
been in electrical connection with the corresponding finger, the charge
stored in the capacitors can be conducted to the chip through the bonding
wire when the wire is first bonded to the chip and then to the
corresponding finger to form an electrical connection between the chip
and the finger. As a result, the current resulted from the charge flow
from the capacitors to the chip is likely to damage the chip.

[0006]Accordingly, there exists a need to provide a method for discharging
electronic devices on a substrate to solve the above-mentioned problems.

SUMMARY OF THE INVENTION

[0007]It is an object of the present invention to provide a method for
discharging electronic devices on a substrate. Prior to wire bonding from
a chip to a finger on the substrate, the charge previously stored in the
electronic devices is discharged in order to prevent the current from
occurring due to an electrical connection between the chip and the finger
formed in the wire bonding process to damage the chip.

[0008]In one embodiment, the method for discharging electronic devices on
a substrate is to provide a wire bonder with a metal pin electrically
connecting to the wire bonder. When wanting to discharge an electronic
device, such as capacitor on a substrate, the metal pin is brought into
electrical contact with a specific finger which is in electrical
connection with the electronic device. As a result, the charge previously
stored in the electronic device will be conducted to the wire bonder
through the specific finger and the metal pin thereby discharging the
stored charge.

[0009]In another embodiment, the method for discharging electronic devices
on a substrate is first to heat a metal wire protruding out from a
capillary of a wire bonder to form a metal ball at the capillary.
Afterward, the capillary is moved to bring the metal ball into contact
with the first portion of the finger. As a result, the charge previously
stored in the electronic device will be conducted to the wire bonder
through the finger, the metal ball and the metal wire thereby discharging
the stored charge.

[0010]The present invention further provides a semiconductor package.
After the metal ball has been formed on the first portion of the finger,
a metal wire is used to electrically connect the chip to the second
portion of the finger. Finally, a sealant is formed on the substrate to
encapsulate the chip, metal ball, metal wire, finger and electronic
device.

[0011]The foregoing, as well as additional objects, features and
advantages of the invention will be more readily apparent from the
following detailed description, which proceeds with reference to the
accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 illustrates the method for discharging electronic devices on
a substrate according to the first embodiment of the present invention.

[0013]FIGS. 2a and 2b illustrate the method for discharging electronic
devices on a substrate according to the second embodiment of the present
invention.

[0014]FIG. 2c illustrates that a metal ball is left on the finger of the
substrate after the performance of the method according to the second
embodiment of the present invention.

[0015]FIG. 3 is a cross-sectional view of the semiconductor package of the
present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016]Referring to FIG. 1, the method for discharging electronic devices
on a substrate according to the first embodiment of the present invention
is to provide a wire bonder 110 with a metal pin 112 electrically
connecting to the wire bonder 110. When wanting to discharge an
electronic device 130, such as capacitor on a substrate 120, the metal
pin 112 is brought into electrical contact with a specific finger 122
which is in electrical connection with the electronic device 130. As a
result, the charge previously stored in the electronic device 130 will be
conducted to the wire bonder 110 through the specific finger 122 and the
metal pin 112 thereby discharging the stored charge.

[0017]The method described above can be performed prior to or subsequent
to the attachment of a chip 140 to the substrate 120 but is required to
be carried out before the wire bonding. This will prevent the current
from occurring due to an electrical connection between the chip 140 and
the specific finger 122 on the substrate 120 formed in the wire bonding
process to damage the chip 140.

[0018]Referring to FIGS. 2a and 2b, the method for discharging electronic
devices on a substrate according to the second embodiment of the present
invention is first to heat a metal wire 214 protruding out from a
capillary 212 of a wire bonder 210 to form a metal ball 216 at the
capillary 212. Afterward, the capillary 212 is moved to bring the metal
ball 216 into contact with the finger 122 at a certain portion, e.g.
first portion 122a. As a result, the charge previously stored in the
electronic device 130 will be conducted to the wire bonder 210 through
the finger 122, the metal ball 216 and the metal wire 214 thereby
discharging the stored charge.

[0019]After the charge stored in the electronic device 130 is discharged,
both the original wire bonder 210 and capillary 212 can continue to be
used to perform the wire bonding from the chip 140 to the finger 122
without need to change the wire bonder 210 and capillary 212.
Accordingly, the time for changing these wire-bonding facilities can be
saved. Furthermore, referring to FIG. 2c, after the capillary 212 is
moved from the finger 122, the metal ball 216 will be secured to the
finger 122 to form a metal ball 124. At this stage, there is no need to
remove the metal ball 124 from the finger 122 in order to proceed with
the wire bonding from the chip 140 to the finger 122. It just needs to
wire bond the chip 140 to the finger 122 at other portion different from
the first portion 122a, e.g. second portion 122b. Besides, according to
the method for discharging electronic devices on a substrate of the
second embodiment of the present invention, the metal wire 214 is not
required to be heated to form the metal ball 216 at the capillary 212 in
order to come into contact with the finger 122 to discharge the charge
stored in the electronic device 130. It just needs to bring the metal
wire 214 directly into electrical contact with the finger 122.

[0020]Referring to FIG. 3, the present invention further provides a
semiconductor package 300. After the metal ball 124 is formed on the
first portion 122a of the finger 122 on the substrate 120, a metal wire
310 is used to electrically connect the chip 140 to the second portion
122b of the finger 122. Finally, a sealant 320 is formed on the substrate
120 to encapsulate the chip 140, metal ball 124, metal wire 310, finger
122 and electronic device 130. The semiconductor package 300 of the
present invention is similar to a conventional one in structure. The
substrate 120 of the semiconductor package 300 also has a portion exposed
out of the sealant 320 on which is provided with output terminals for
electrically connecting to other electronic devices (not shown in the
figure). The output terminals can be common gold fingers, leaders or
solder balls. Because these output terminals are well-known in the art,
any further illustrations of these elements will be omitted herein.

[0021]Although the preferred embodiments of the invention have been
disclosed for illustrative purposes, those skilled in the art will
appreciate that various modifications, additions and substitutions are
possible, without departing from the scope and spirit of the invention as
disclosed in the accompanying claims.